Pop-up sprinkler surrounded by open cell resilient material



W. SEABLOM A ril 30, 1968 POP-UP SPRINKLER SURROUNDED BY OPEN CELL RESILIENT MATERIA' Filed Nov. 26, 1965 w M %m r LFIQM WG e .tl mS F. M -m i. 6 H W. w L g F A Attorneys United States Patent 3,380,659 POP-UP SPRINKLER SURRGUNDED BY OPEN CELL RESILIENT MATERIAL Wendell Seahlom, 3712 Texas Drive, Santa Rosa, Calif. 95405 Filed Nov. 26, 1965, Ser. No. 509,910 3 Claims. (Cl. 239-205) ABSTRACT OF THE DISCLOSURE A hydraulically operated linear actuator, particularly is useful in a lawn sprinkler of the pop-up type, employs an expansible protector sleeve encircling the projectable stem of the unit. The expansible sleeve is of an open cell material whereby to absorb moisture and upon withdrawal of the projected member, captured moisture within the sleeve acts to purge dirt and other foreign matter therefrom.

This invention relates to hydraulically operated linear actuators, and particularly to lawn sprinklers of the popup type.

One type of sprinkler used with undergorund water sprinkling systems employs a piston that is hydraulically reciprocated between elevated and lowered positions. The sprinkler head is attached to a hollow stem which extends into the body in which the piston is disposed. The exposed portion of the stern and the seal between the stem and the body are subject to accumulation of materials such as dirt and other debris. This is objectionable in that it causes excessive wear of the stem and seal and may interfere with proper operation. As a result, such sprinklers may require frequent repairs or replacement to maintain the system in proper operation.

In general, it is an object of the present invention to provide an improved hydraulic linear actuator which overcomes the above disadvantages.

A further object of the invention is to provide a lawn sprinkler having means which protects the seal and riser stern against dirt or other debris.

A further object of the invention is to provide a lawn sprinkler having a protector which is self-purging during operation.

A further object of the invention is to provide a lawn sprinkler of the above character which uses a protector constructed of open cell, porous material which absorbs water during operation of the sprinkler and which squeezes out the water as the sprinkler stem is lowered to thereby purge the protector of entrapped dirt.

Another object of the invention is to provide a lawn sprinkler of the above character having a protector constructed as a one piece unit adapted for ready removal and installation on the sprinkler without requiring the sprinkler to be disconnected from associated piping or to be removed from the ground.

Another object of the invention is to provide a lawn sprinkler having a protector of the above character which functions as a check valve to close the flow passage within the sprinkler when the applied water supply pressure falls below a predetermined value.

Further objects and features of the invention will appear from the following description in which the preferred embodiment of the invention has been set forth in detail in conjunction with the accompanying drawings.

Referring to the drawings:

FIGURE 1 is an elevational view, partly in cross-sew tion, of a pop-up lawn sprinkler constructed according to the teachings of the invention and showing the riser stem withdrawn and the protector collapsed.

FIGURE 2 is a top plan view of the sprinkler taken along the lines 2-2 of FIGURE 1.

FIGURE 3 is a side elevation view taken along the lines 33 of FIGURE 2.

FIGURE 4 is a side elevational view, partly in section, of the sprinkler of FIGURE 1 and showing the riser stem in the raised position and the protector expanded.

Referring to the drawings, there is shown a pop-up sprinkler of the type commonly embedded in the ground. The sprinkler comprises an elongated tubular body 10 having a bore 11 therein to form a cylinder. The lower end portion of the body 10 is provided with the end closure 12. A pipe 13 communicates with the bore 11 through the lower sidewall of the body and serves to connect the bore 11 with a source of water under pressure.

An elongate, hollow post 14 is mounted axially within the body 10 and extends between its ends, the lower end of the post being secured to the closure 12. The space 15 surrounding the post 14 forms an annular flow passageway for water to pass through the sprinkler. The upper end portion of the post is provided with slots 16 to permit water to flow therethrough.

A piston 17 is slidably fitted within the bore 11 for reciprocation between elevated and lowered positions. The piston is suitably sealed, as by means of seal rings 18 and 19 of the resilient O-ring type which are accommodated in annular grooves formed in the piston.

A hollow riser stem 21 extends through the upper end of the body and is secured to the piston 17. Its inner diameter is greater than the outer diameter of post 14 so that it may reciprocate relative to the post between elevated or extended and lowered or retracted positions. When fully extended, the piston O-ring seal 19 is advanced to a position beyond the slots 16 of the post 14 so that water below the piston may pass upwardly through the slots and into the hollow stem 21.

The upper end of the body 10 is closed by an annular closure member 22 having a duct or passage 23 extending from one side thereof, the duct being connected to the exterior tube or down spout 24 for purposes hereinafter described. The opening 26 in member 22 is dimensioned to slidably accommodate the stem 21. Leakage between the stern and closure member 22 is prevented by suitable sealing means, such as of the O-ring type. Thus, groove 27 is provided about the periphery of the opening 26 and serves to accommodate the resilient O-ring 28.

A sprinkler head or nozzle 31 is attached to the upper end of stem 21 and serves to discharge water flowing through the stem in a desired spray pattern. 'The nozzle 31 may be provided with raised portions 32 for facilitating screwing of the same into the stem.

It will be evident that any water in the space above of piston 17 is expelled through the passage 23 and tube 24 as the piston moves upwardly. As is seen, water supplied under pressure through the pipe 13 at the lower end of the body 10 serves to force the piston upwardly until the same has passed over the slots 16 of the post 14 so that water may flow through the slots and upwardly through the stem 21 for discharge as a spray from the sprinkler nozzle 31.

When the supply of water is turned off, the riser stem 21 is positively retracted into the body 10 by the application of a control water pressure through the tube 24 and thence to the upper side of the piston 17 to thereby force the piston downwardly into the body until the piston seats on the stop or spacer members 33 provided in the lower portion of the body. Various materials can be used for the various parts of the sprinkler, such as suitable metal or metal alloy or plastic, such as a copolymer of acrylonitrile-butadiene-styrene (ABS).

A sprinkler of the type described above is disclosed in my copending patent application for Sprinkler Head 3 and System, Ser. No. 407,255, filed Oct. 28, 1964, now Pat. No. 3,263,929.

Mounted on top of the sprinkler body 10 and disposed about the stem 21 there is a protector 40 shown in collapsed form in FIGURES 1-3, and in expanded form in FIGURE 4. The protector 40 comprises a cylindrical member 41 formed of an open cell, sponge-like resilient material. By way of example, a soft or super-soft flexible polyurethane foam having a very low load bearing characteristic has been found satisfactory.

The member 41 is formed in the shape of a hollow cylinder having an interior dimension slightly larger than the stem 21 (eg. from approximately one-sixteenth of an inch to one-eighth of an inch larger), so that there will be room for collapsing the member 41 about the stem without binding. The wall thickness of the member 41 is made large enough to ensure an adequate Water absorption capacity. For example, a thickness of from about one-fourth of an inch to one-half of an inch has been found adequate for a sprinkler head of the type shown.

The cylindrical member 41 is disposed between annular support members 42 and 43 of disk-like form which are constructed of any suitable rigid material, such as ABS plastic, The members 42 and 43 are formed to provide annular recesses 42a and 43a within which the corresponding ends of the protective element are seated. Preferably members 42 and 43 are attached to the ends of element 41 as by means of a suitable cement or adhesive (cg. epoxy resin).

It is desirable for member 42 to be adapted to be snap engaged with the top of the body 10. Therefore it is provided with a plurality of downwardly extending legs 44 having lower portions 440 thereof extending toward each other. When the member 42 is forced down upon the top of the sprinkler body, the legs are sprung outwardly to slip past and engage the shoulder or rib 22a on annular recess 42b adapted to retain a resilient washer 45 that forms a seal between the top of the member 22 and member 42.

Member 43 is provided with an annular flange 46 adapted to contact the upper end of the stem 21. The sprinkler head is dimensioned whereby when it is threaded upon the stem, member 43 is loosely retained between the upper end of the stem and the head (FIGURE 4). In other words, the stern and the retaining portion loosely restrain the member 43 axially and in general alignment with the stem but leave it rotationally free. If the sprinkler head and stem should rotate, the cylindrical member 41 is not twisted. However, axial movement of the stem carries the member 43 along to thereby open or collapse the protector.

Operation of my device is as follows:

Reference is made particularly to FIGURE 3 which shows the riser stem 21 in fully lowered or retracted position with the cylindrical member 41 being fully collapsed so that it lies within the annular recesses 42a and 43a provided in the support members 42 and 43. The volume of the combined annular recesses is such that there is just enough space for the collapsed member 41.

Referring now particularly to FIGURE 4, the sprinkler is shown with the riser stem in fully elevated or extended position due to water pressure acting upon the lower surface of the piston 17. The member preferably is made to have a length slightly less than the distance between the support members 42 and 43 when the stem is fully extended. Therefore, when fully extended as in FIGURE 4, it is somewhat stretched in the direction of its length, whereby its medial portion is of a diameter somewhat less than the diameter when the element is relaxed. During operation of the sprinkler, the mist generated by the water being sprayed by the sprinkler, as well as water spray from other sprinklers in the vicinity, is suflicient to load the cylindrical member 41 with water. Any dirt or other debris which may accumulate on member 41 during a sprinkling cycle is washed or squeezed out as the protector is collapsed at the end of the cycle, at which time the riser stem is retracted to collapse the member 41. Thus, at all times the entire length of the riser stem from the top of the sprinkler body to the top of the riser stem and the seal between the stem and the body, are protected and it is virtually impossible for dirt, silt, or other foreign matter to come into contact with the stem or the seal.

Referring again to FIGURE 4, there is shown in dotted lines the position 47 assumed by the various parts when the water pressure falls below a predetermined value, and before the riser stem is positively retracted. Under such circumstances, the tensioned member 41 pulls on member 43 to move the riser stem downwardly a short distance thereby bringing the O-ring piston seal 19 below the slots 15, and cutting off communication between the inside of the stem 21 and the bore 11 below the piston. By this action the sprinkler serves as its own automatic check valve to prevent back flow of water from the outside of the sprinkler into the water supply line when the water pressure fails.

It is apparent from the foregoing description and drawing that my invention has peculiary advantageous application to lawn sprinklers. Thus, the invention serves to prevent windborne dust and other silt from contacting the riser stem of the sprinkler. At the same time, any water mist or spray contacting the protector is taken up into the open cell structure of the resilient member from whence it is squeezed out as the stem is retracted in shutting off the sprinkler. As the water is squeezed out, the accumulated dirt, etc. is automatically purged out with the water.

Although I have shown the invention embodied in a lawn sprinkler, there are other types of linear actuators to which the invention is deemed to be applicable. For ex ample, the invention can be incorporated in a hydraulic jack or hoist of the automotive type. In this instance, the protective element is disposed about that portion of the lift post adjacent the seal between the post and the body, whereby it is collapsed when the post is fully lowered, and expanded when the post is raised.

I claim:

1. In a lawn sprinkler, a body forming a cylinder, a piston slidably disposed within the cylinder, a hollow stem secured to the piston and extending to the exterior of the body, a sprinkler head mounted at the exterior end of said stem, and a protector comprising a cylindrical member shaped in the form of a hollow cylinder having an interior dimension slightly larger than the stem, a pair of support members of disk-like form, each of said support members having an annular recess on one side thereof for receiving the corresponding ends of the cylindrical member, the ends of said cylindrical member being secured within the recesses, one of said members being provided with means for attachment to the body of said sprinkler, the other of said members being loosely connected to the top of the stem in such manner that the member is free to rotate relative to the stem but is loosely longitudinally restrained so that as the stem is reciprocated with respect to the body said protector is collapsed and permitted to expand.

2. In a lawn sprinkler, a body forming a cylinder, a piston slidably disposed within the cylinder, a hollow stern secured to the piston and extending to the exterior of the body, a sprinkler head mounted on the exterior end of said stem, and a protector comprising a cylindrical member formed of an open cell resilient material surrounding said stem in the region adjacent to where the stem enters the body, said protector being collapsed and permitted to expand as the stem is reciprocated, said protector including an annular support member secured to that end of the cylindrical member remote from the body, said support member being loosely connected to the stem adjacent the sprinkler head.

3. In a lawn sprinkler, a body forming a cylinder, a piston slidably disposed within the cylinder, a hollow stem secured to the piston and extending to the exterior of the body, a sprinkler head mounted on the exterior end of said stem, and a protector comprising a cylindrical member formed of an open cell resilient material surrounding said stern in the region adjacent to where the stem enters the body, said protector being collapsed and permitted to expand as the stem is reciprocated, said protector being dimensioned to be stretched under tension as the stem is fully extended by the action of Water pressure, and to pull the stem slightly back from its fully extended position when the water pressure falls below a predetermined value, and said sprinkler further including water flow path through the sprinkler when the stem is slightly retracted.

References Cited UNITED STATES PATENTS 1,953,518 4/1934 Sweetland 23 9--204 2,399,112 4/1946 Glover 239-205 2,405,093 7/1946 LaBrie 92l6 8 X 2,411,229 11/ 1946 Pratt 92-168 3,002,696 10/1961 Jenkins 239204 X 3,033,467 5/1962 Hofer 239-204 3,258,205 6/1966 Hruby 239204 M. HENSON WOOD, JR., Primary Examiner.

means responsive to the position of the stem to close the 15 VAN WILKS, Assistant Examiner. 

